1. Field of the Invention
The present invention relates to a system and method for reading two-dimensional barcode symbologies. More particularly, the present invention relates to a system and method for reading a two-dimensional barcode using a CCD optical scanning head.
2. Description of Related Art
Barcode symbology provides an efficient and beneficial method by which to store and convey data. Thus, many industries have adopted the barcode format to facilitate processing of all kinds of information.
Conventional barcodes are presented in a "one-dimensional" format. In one-dimensional barcodes, a series of bars and spaces having varying widths are provided in a single horizontal line. Each bar and space in the line represents a piece of the information carried in the one-dimensional barcode. Taken together, the bars and spaces represent the totality of the message to be conveyed by the barcode. The actual information contained in each bar and space depends on its width.
One-dimensional barcodes are limited, however, in the amount of information they can store and convey. Because such a barcode contains all its bars and spaces in a single line, to handle more than a small amount of information, the barcode must be made longer and/or the bars and spaces narrower. Substantial lengthening of a one-dimensional barcode, however, is impractical, and the bars and spaces cannot be made too narrow, because barcode scanners would be unable to read them.
Accordingly, a new barcode architecture has been developed, known as "two-dimensional" barcode symbology. Two-dimensional barcodes contain more than one line of bars and spaces, the lines being stacked to create a rectangular symbol. In other words, a two-dimensional barcode has horizontal and vertical components. With lines of bars and spaces stacked in two-dimensional format, substantially more information can be stored in a single two-dimensional barcode than in one-dimensional barcodes.
Nevertheless, with the added complexity of stacking lines of bars and spaces on top of each other, two-dimensional barcodes have created new problems in scanning and reading technology. While scanning heads do exist that can operate to read two-dimensional barcodes, no system or method has been developed that can operate accurately and efficiently, but at the same time without the necessity of expensive equipment, such as laser scanning heads. Such a system would incorporate CCD scanning heads, which are less costly than laser scanning heads, and yet can accurately read two-dimensional barcodes.
Therefore, a need exists for a system and method for reading two-dimensional barcode symbologies that is accurate, efficient, and inexpensive, in particular that incorporates a CCD optical scanning head.